1. Field of the Invention
The invention relates to the field of crimping or other press machines having a ram which is movable into proximity with a base for engaging a workpiece therebetween, and more particularly, to a device for adjusting the closest proximity of the ram with respect to the base in a press machine.
2. Prior Art
Numerous types of press machines are used in industry for performing operations on a workpiece. The press machines typically have a ram which reciprocates toward and away from a base for engaging the workpiece therebetween. One type of press machine is an automatic crimping machine for crimping terminals to electrical conductors.
Various types of terminals may be deformed, or crimped, around electrical conductors to provide an electrical connection therewith. A terminal crimping machine typically comprises a tooling ram carrying a crimping die which reciprocates toward and away from a base of the machine. The crimping die cooperates with an anvil die attached to the base to deform a terminal disposed therebetween when the crimping die is in proximity with the anvil die.
Height of the terminal after deformation is referred to as the crimp height. The crimp height is a valuable indicator of quality of the crimped connection. A crimp height that is too large will not provide a secure and reliable connection, while a crimp height that is too small results in excessive deformation which will weaken or break the terminal and/or conductor, and in addition wastes energy in driving the machine.
The crimp height is a function of shut height of the machine, i.e., a dimension between the crimping die and the anvil die when the crimping die is in its closest proximity with respect to the anvil die. The shut height may need to be changed to accommodate different sizes and types of terminals and/or conductors which require different crimp heights. Also, the shut height may need adjustment to compensate for such things as tooling wear, dimensional tolerances of replacement parts, and dimensional changes due to temperature variations.
Devices for adjusting the shut height of automatic crimping machines are known. U.S. Pat. No. 3,184,950 to Sitz discloses a shut height adjusting device for an automatic crimping machine having a power, or press, ram which drives a tooling ram carrying the crimping die toward the anvil die. The adjusting device comprises a rotary disc interposed between the press and tooling rams. A side of the disc facing the press ram has a plurality of pairs of bosses of different heights. Contact arms of the press ram bear against selected pairs of the bosses during a crimping stroke of the press ram, thereby governing a spaced relationship between the press and tooling rams. The disc is rotatable to selectively position different pairs of the bosses for engagement by the contact arms, thereby changing the spaced relationship between the rams and thus the shut height of the machine. A detent mechanism is provided to ensure that the selected bosses are aligned with the contact arms and are maintained in position until a different selection is made. Although the Sitz device performs adequately, the disc is expensive to manufacture because it is an integral metal unit and the bosses must be machined to close dimensional tolerances. If one of the bosses is machined incorrectly the entire disc may be ruined, and when a boss becomes worn or damaged in use, the entire disc must be replaced with a new disc having bosses machined to correct dimensions. Furthermore, a single disc has only four pairs of bosses which provide four different crimp heights, and a plurality of discs must be stocked to cover a broad range of different crimp heights.
U.S. Pat. No. 4,790,173 to Boutcher, Jr., discloses a shut height adjustment device comprising a mounting block fixed to the press ram and a dial rotatably secured between the mounting block and the tooling ram. Facing surfaces of the mounting block and the dial define opposed helical ramps. A change in angular position of the dial causes the ramps to ride over each other, whereby the dial is axially displaced with respect to the press ram and shut height of the machine is changed. The device of Boutcher, Jr., enables infinite adjustment of crimp height between upper and lower limits. However, the device does not enable a particular crimp height to be quickly and easily selected because the angled ramps do not provide natural zones associated with discretely different crimp heights. Production of a desired crimp height is attainable primarily after making a series of adjustments while zeroing in on the desired crimp height through trial and error.
The present invention overcomes the problems of the prior art shut height adjustment devices by providing a carrier which removably holds a plurality of spacers for selective interposition between the press and tooling rams. The spacers are simple and inexpensive to produce so that a large inventory of the spacers precisely machined to different heights can be stocked. The spacers are easily interchangeable in the carrier so that a large number of discrete crimp heights is obtainable.